1. Field of the Invention
The present invention relates to a semiconductor integrated circuit comprising a plurality of functional blocks such as signal processing circuits. In particular, power consumption of each functional block can be realized.
2. Related Art
A conventional method of measuring power consumption of a semiconductor integrated circuit is explained below.
First, a semiconductor integrated circuit is mounted onto a circuit board. Next an ammeter is connected to power supply wiring prepared on the circuit board. Then, the circuit board and the semiconductor integrated circuit are operated. The ammeter measures the current passing through the power supply wiring prepared on the circuit board, and a measured current value is used for calculating the power consumption of the semiconductor integrated circuit.
If it is impossible to connect the ammeter to the circuit board (because of any reason, for example, the circuit board is built in a cabinet, and so on), applying the conventional measuring method as described above cannot measure the power consumption of the semiconductor integrated circuit.
Moreover, in case a plurality of semiconductor integrated circuits together with registers and so on are connected to a single set of power supply wirings prepared on a circuit board, applying the conventional measuring method as described above does not make it possible to realize power consumption of each device.
Furthermore, a semiconductor integrated circuit comprising a plurality of functional blocks that each operate in synchronization with a plurality of different clock signals has recently come into use. However, applying the conventional measuring method as described above does not make it possible to realize power consumption of each of the functional blocks inside the semiconductor integrated circuit.
Incidentally, a type of counter device, which has its counter operate to reduce power consumption only when needed, is known. (For example; refer to Japanese Patent Laid-Open Publication No. 2000-49593 (first page and FIG. 1)).
However, such a counter device described in Japanese Patent Laid-Open Publication No. 2000-49593 does not make it possible to measure power consumption of each of a plurality of functional blocks placed internally.
Furthermore, a type of semiconductor integrated circuit device and equivalent, in which a determination on supplying a clock signal is made for each module, is also known. (For example; refer to Japanese Patent Laid-Open Publication No. 2000-148284 (first page and FIG. 1)).
However, such a semiconductor integrated circuit device and equivalent described in Japanese Patent Laid-Open Publication No.2000-148284 do not make it possible to measure power consumption of each of a plurality of signal processing circuits placed internally.
Taking the points described above into consideration, the present invention aims to provide a semiconductor integrated circuit which comprises a plurality of functional blocks such as signal processing circuits and so on, and in which the power consumption of each functional block can be determined.